[PATCH v1 5/8] x86/entry/clearregs: Clear registers for 64bit exceptions/interrupts

From: Andi Kleen
Date: Tue Jan 09 2018 - 20:05:13 EST


From: Andi Kleen <ak@xxxxxxxxxxxxxxx>

Clear all registers on entering the 64bit kernel for exceptions and
interrupts.

Since there are no arguments this is fairly simple.

Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
---
arch/x86/entry/entry_64.S | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 632081fd7086..6ab4c2aaeabb 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -636,6 +636,7 @@ END(irq_entries_start)
ALLOC_PT_GPREGS_ON_STACK
SAVE_C_REGS
SAVE_EXTRA_REGS
+ CLEAR_ALL_REGS
ENCODE_FRAME_POINTER

testb $3, CS(%rsp)
@@ -1192,6 +1193,7 @@ ENTRY(xen_failsafe_callback)
ALLOC_PT_GPREGS_ON_STACK
SAVE_C_REGS
SAVE_EXTRA_REGS
+ CLEAR_ALL_REGS
ENCODE_FRAME_POINTER
jmp error_exit
END(xen_failsafe_callback)
@@ -1237,6 +1239,7 @@ ENTRY(paranoid_entry)
cld
SAVE_C_REGS 8
SAVE_EXTRA_REGS 8
+ CLEAR_ALL_REGS
ENCODE_FRAME_POINTER 8
movl $1, %ebx
movl $MSR_GS_BASE, %ecx
@@ -1289,6 +1292,7 @@ ENTRY(error_entry)
cld
SAVE_C_REGS 8
SAVE_EXTRA_REGS 8
+ CLEAR_ALL_REGS
ENCODE_FRAME_POINTER 8
xorl %ebx, %ebx
testb $3, CS+8(%rsp)
@@ -1487,6 +1491,7 @@ ENTRY(nmi)
pushq %r14 /* pt_regs->r14 */
pushq %r15 /* pt_regs->r15 */
UNWIND_HINT_REGS
+ CLEAR_ALL_REGS
ENCODE_FRAME_POINTER

/*
--
2.14.3